The invention relates more particularly to a safety accessory for use during braking under the control of the users of such vehicles.
The braking means of such vehicles comprise drum brakes, brakes controlled by back-pedalling, hydraulic or pneumatic brakes, and friction brakes engaging the wheel rims.
The invention relates more particularly to vehicles of the general type mentioned in the introduction, provided with braking systems that are controlled by cables.
This applies in particular to brakes that apply friction to rims. By way of example, such brakes can be of the caliper or V-brake type, where caliper brakes comprise jaws, sometimes also referred to as hinged levers or brackets, said jaws being provided with brake blocks having friction linings, and the jaw is caused to clamp onto the wheel rim under the control of a cable. The cable is conventionally moved by working a lever mounted on the vehicle handlebar, the control cable connecting said lever to the brake jaws. When the lever is actuated, the control cable is pulled under tension in its guide tube and causes the brake jaws to close, thereby giving rise to friction between the brake linings and the wheel rim. Return springs or any other equivalent resilient means serve to return the jaw to an open position when the control lever is released. Cable traction can be applied centrally or laterally. Conventionally, each wheel is provided with a brake jaw connected by a respective control cable to a lever mounted on the handlebar.
For safety reasons, it is most important for cyclists to be visible to other road users, particularly in the dark, and in particular when cyclists apply the brakes, insofar as such braking often precedes a change in direction.
Various systems are already known in the prior art for controlling braking signal lamps for cycles.
Reference can be made, for example, to the following documents: FR-A-2 756 803, FR-A-2 708 557, FR-A-2 652 052, DE-A-19 633 018, DE-A-19 654 628, DE-A-19 808 774, U.S. Pat. No. 5,526,240, U.S. Pat. No. 5,457,612, U.S. Pat. No. 4,899,023, U.S. Pat. No. 4,275,280, U.S. Pat. No. 4,031,343, U.S. Pat. No. 3,906,443, U.S. Pat. No. 3,870,846, GB-A-2 236 905, GB-A-2 229 052, GB-A-2 130 015, WO-A-91/12977.
Certain prior art devices propose placing contactors on the handlebar. Thus, for example, document EP-A-0 109 763 describes a bicycle brake light switch comprising electrical contacts contained in a deformable closed tube that is flattened under direct action from the brake lever. In that type of structure, detecting braking relies on the shape of the tube being appropriate relative to the shape and the stroke of the brake lever, and as a result that structure cannot be fitted as standard on all types of cycles. Furthermore, it is difficult to monitor the state of the electrical contacts contained in the closed tube without resorting to complete disassembly.
Other types of prior art device have contactors that are placed closer to the braking jaws. Thus, for example, document WO-A-86/00055 describes braking equipment for a bicycle in which a lamp is switched on by one of the brake jaws coming into contact with a terminal of the electrical circuit. That type of configuration turns out to be unreliable when cycles are used in muddy terrain.
The control systems known in the prior art turn out to be complex and expensive in structure. In addition, those systems are not as a general rule designed to be suitable for fitting on any type of existing cycle. The fragility of certain means known in the prior art for detecting brake cable movement also tends to make them unreliable, particularly when the cycle has been used on muddy surfaces.